Hi, sorry for the late response.
It might be the case that you had previously some plugin or other theme settings that were generating images at 200x200px, or, perhaps, one of the images sizes you currently use was altered and it does not read 200px anymore. If you have access in the database to see the objects meta, and have an exact example of image that is cut to 200x200px, we can take a look and identify exactly the name of the image size, then you can decide what to do about these. Let me know if you need my help with it.